SEC-722: Add Open ID Namespace Support

http://jira.springframework.org/browse/SEC-722. Added check for MAIN_ENTRY_POINT bean when resolving entry points. If this has been set during parsing it will be used.

core/src/main/java/org/springframework/security/config/HttpSecurityConfigPostProcessor.java

@@ -152,7 +152,11 @@ public class HttpSecurityConfigPostProcessor implements BeanFactoryPostProcessor
         if (entryPoints.size() == 1) {
             mainEntryPoint = (AuthenticationEntryPoint) entryPoints.get(0);
         } else {
-            mainEntryPoint = (AuthenticationEntryPoint) entryPointMap.get(BeanIds.FORM_LOGIN_ENTRY_POINT);
+            mainEntryPoint = (AuthenticationEntryPoint) entryPointMap.get(BeanIds.MAIN_ENTRY_POINT);
+            
+            if (mainEntryPoint == null) {
+            	mainEntryPoint = (AuthenticationEntryPoint) entryPointMap.get(BeanIds.FORM_LOGIN_ENTRY_POINT);
+            }
 
             if (mainEntryPoint == null) {
                 mainEntryPoint = (AuthenticationEntryPoint) entryPointMap.get(BeanIds.BASIC_AUTHENTICATION_ENTRY_POINT);